With the rapid development of information society, the importance of copying enormous amount of records accumulated over a long period of time rapidly and correctly, and preparing records which will stand up to prolonged storage at low cost, and further recording enormous informations generated as a result of daily economical activities (output information of computers) at high speed, classifying, distributing and storing them for a long time are increasing. Silver halide photosensitive materials occupy an important position as is well known in the art as materials which satisfy these requirements. For example, microfilms for documents (Source Document Microfilm) and COM film (Computer Output Microfilm) are commercially available.
The characteristics required for microfilms and COM films include i) high density recordability (high resolving power) as well as ii) high speed recordability (photographic sensitivity), iii) high speed development processability and iv) permanent storability, etc. Of these characteristics required, silver halide photosensitive materials are quite suitable for items i), ii) and iv), but silver halide photosensitive materials are not necessarily satisfactory for item iii). To overcome this defect, various efforts have been made in the art.
More specifically, to increase the development processing speed, the amount of silver coated has been suppressed to the necessary minimum in designing the photosensitive material. Further, to increase the drying speed after development processing water washing, the amount of a hydrophilic binder (e.g., gelatin) coated on the support is also reduced to the necessary minimum. Moreover, these photosensitive materials, after high temperature development processing, are further quickly dried at a high temperature, and, therefore, if fine water droplet irregularity remains on the surface of the photosensitive material depending on the manner of operation of squeeze rollers or the clearance of squeeze blade of the automatic developing machine, drying irregularity by quick drying thereafter tends to occur. As a result, fine image density irregularity tends to be generated. Some of these image density irregularities can be observed with the naked eye, but these are not under discussion here. Most of the irregularities which pose a problem in microfilms can be observed with the naked eye with extreme difficulty, but could be observed with a loupe. In the field of microphotography, the recorded image is observed enlarged by a factor of 40-fold or more. Even a fine density irregularity not only reduces the finished image quality, but can also result in a deficiency in the recorded information, whereby an extremely serious problem can arise as to its commercial value as microfilm and COM film.
The fine image density irregularity found after development processing drying in microfilm and COM film as mentioned above has been known for a long term, but the mechanism of its generation cannot be said to be sufficiently clarified at this time. I has been believed that fine water droplet irregularity formed after development processing water washing causes drying irregularity to occur when the material is dried quickly at a high temperature, thereby moving image silver particles.
The fine image density irregularity occurring after development processing drying has been long called water marks and also as water spots. The need for a microfilm or COM film in which water marks or water spots are not generated or which are generated only with difficulty even under severe conditions where sufficient control of an automatic developing machine does not occur is great.